Is jBoss architected in such a way that it can support multiple instances of the same entity bean in a single transaction? If so, please share how to do ths and skip the rest of this post.
Many other highly-scalable application servers (Borland, WebLogic) will create a new instance of a bean that is marked as non-reentrant. This guarantees thread safety and dramatically increases throughput on large systems.
WebLogic took the same approach as jBoss earlier in its development cycle, however the > 5.0 series have switched to this more scalable approach.